KR980010427A - Diagnostic test carriers with multilayer test fields and methods of use thereof for the determination of analytes - Google Patents

Abstract

The present invention includes a sample application surface to which a blood sample is applied and a detection surface where an optically detectable change occurs as a result of the reaction of the analyte and the reagent system, and the red blood cells present in the sample do not reach the detection surface. A diagnostic test carrier for measuring analyte from whole blood using a reagent system contained in a carrier comprising a designed test field and a color forming reagent, wherein the test field is placed on top of each other. A transparent foil coated with the first and second film layers is included, and the first layer positioned on the transparent foil scatters considerably less in wet state than the covering second layer, so that the first layer coated with the first layer opposite to the thin surface is coated. The surface of the second layer opposite to the surface on which the second layer is placed on the first layer is a detection surface, and the sample is applied to a diagnostic test carrier.

The present invention also relates to a method for measuring an analyte from whole blood using a diagnostic test carrier according to the present invention.

Description

[Name of invention]

Diagnostic test carriers with multilayer test fields and methods of use thereof for the determination of analytes

Detailed description of the invention

[Technical Field to which the Invention belongs and Prior Art in the Field]

The present invention includes a sample application site into which a blood sample is introduced and a detection surface on which an optically detectable change occurs as a result of the reaction between the analyte and the reagent system, and the red blood cells present in the sample do not reach the detection site. The present invention relates to a diagnostic test carrier for measuring analyte from whole blood using a reagent system contained in a test carrier including a test field and a color developing reagent. The invention also relates to a method for measuring an analyte from whole blood with a diagnostic test carrier according to the invention.

So-called carrier binding tests are often used for the qualitative or quantitative determination of components in body fluids, particularly blood. Wherein the reagent is present in or on an appropriate layer of the solid test carrier in contact with the sample. The reaction of the liquid sample with the reagents results in a change in color that can be detected by a detectable signal, in particular by the naked eye or on an instrument, typically a reflectometer.

The test carrier is generally in the form of a test strip consisting of a stretchable support layer consisting primarily of plastic material and a test field consisting of one or several detection layers thereon. However, test carriers in the form of small square or rectangular foils are also known.

Carrier binding tests are particularly characterized by their ease of handling. Thus, for most test carriers previously known, it is more regrettable that sample liquid blood cannot be used directly in the form of whole blood. In contrast, it is necessary to separate red blood cells to obtain a colorless spot or serum. This is usually done by centrifugation. However, this requires additional manipulation steps that require a relatively large amount of blood and complex devices.

Thus, many attempts have been made to provide test carriers capable of performing analytical measurements directly from blood. One can distinguish between two fundamentally different solutions.

In the first approach, discoloration is assessed using the naked eye or a device on the same side of the test field to which the sample is applied. In this case, the structure of the test field is such that the analyte from the sample reaches the reagent through the surface of the test field while the red blood cells are retained. After a predetermined time has elapsed, the blood sample is wiped off or washed from the surface of the test field to observe discoloration. Examples of such test carriers are described in US-A-3,630,957 and EP-A-O 217 246.

In a second approach, the sample is applied to one side (sample application side) of the test field, and discoloration is seen on the other side (detection side). The main advantage of this method is that there is no need to wipe or clean the blood. Therefore such test carriers are also called non-wipe test carriers.

The omission of stealing eliminates not only one cumbersome manipulation step, but also the possibility of mistakes that may occur if the timing of blood scavenging is not followed correctly. On the other hand, this approach is particularly difficult to achieve. On the one hand, there is a need to concentrate reliably on the pigmented components of the blood, and on the other hand, there is a need for a red blood cell filter that can pass the analyte completely and quickly. Finding test field structures that meet these requirements has proved extremely difficult.

Separation of serum or plasma on test carriers using glass fibers is known from EP-A-O 045 476. This solution may be used universally, but it is necessary to load the fiberglass layer onto the test carrier in a suitable manner. This results in a relatively complex structure of test carriers, which complicates the manufacturing process. In addition, the glass fiber layer absorbs the liquid and becomes unavailable in the detection layer. This means that a relatively large amount of sample is required.

A test field having a laminated structure produced by liquid lamination of a detection layer containing a color forming reagent on a substrate layer facing the sample application surface is known from EP-A-O 302 287. The base layer contains a polymerizable film former, a kieselguhr and a pigment. The detection layer contains a polymeric film former that partially penetrates into the substrate layer during liquid coating and forms a transition region in which red blood cells are retained. However, as can be seen from the examples, the layer containing the pigment is less than 10 times thicker than the detection layer. This has a significant impact on the volume requirements of these test fields. Since only the transition region between the pigment-containing layer and the detection layer serves as the red blood cell holding area, a relatively large volume (of the pigment-containing layer) must be filled with liquid before the detection layer is filled with liquid.

Since none of the previous implementations of NW test carriers with erythrocyte separation show satisfactory properties in all respects, separation of erythrocytes is omitted entirely in commercially available embodiments of such test carriers and interferes with intense reddening. Is calibrated by measuring technique by measuring at two different wavelengths. This significantly complicates the instrument evaluation and cannot be visually inspected for discoloration.

[Technical problem to be achieved]

It is an object of the present invention to provide a test carrier which can be easily prepared and can easily and quickly measure an analyte from whole blood. This measurement should be independent of hematocrit even though it requires only a very small amount of blood. Sample detection should include the possibility of visually assessing the analyte concentration. This object is achieved by the present invention as defined in more detail in the claims.

[Configuration and Function of Invention]

A subject of the present invention is a diagnostic test carrier for the measurement of an analyte from whole blood using a reagent system contained in a test carrier containing a color forming reagent. The test carrier includes a test field having a detection surface in which, in addition to the sample application surface to which the blood sample is applied, an optically detectable change occurs as a result of the reaction between the analyte and the reagent system. Red blood cells in the blood do not reach the detection surface. According to the present invention, the test field comprises a transparent foil coated with first and second film layers, which are placed on top surfaces of each other in the following order. It is important that the first layer located on the transparent foil scatters the debt considerably less than the second layer overlaid. The uncoated surface of the transparent foil is called a detection surface, and the surface of the second layer on the opposite side to the surface on which the second layer is placed on the first layer is called a sample application surface.

In addition, the present invention relates to a method for detecting an analyte from whole blood using a diagnostic test carrier according to the present invention. To this end, blood is applied to the sample application surface of the test field, and the discoloration of the detection surface is observed, and the color formation intensity is the size of the amount of analyte in the irradiated blood sample.

The film layer of the diagnostic test carrier according to the invention is prepared from a dispersion or suspension of the polymerizable film former. Dispersion film formers contain micropolymer particles that are insoluble in the carrier liquid (usually water) and are finely dispersed in the carrier liquid. If the liquid is removed by evaporation during film formation, the particles come close to each other and are in fine contact with each other. The large forces that occur in this process and the increase in surface energy accompanied by film formation result in particles that grow into a substantially closed film layer. Alternatively it is also possible to use emulsions of film formers in which the film former is dissolved in a solvent. The dissolved polymer is emulsified in a carrier liquid that is immiscible with the solvent.

Polyvinyl esters, polyvinyl acetates, polyacrylic esters, polymethacrylic acid, polyvinyl amides, polyamides and polystyrenes are particularly suitable as polymers for such film formers. Also suitable are polymerized materials, such as butadiene, styrene or maleic acid esters, in addition to homopolymers.

Two so-called film layers are placed on the transparent foil in the test field of the diagnostic test carrier according to the invention. To do this, one can think of a plastic foil that is impermeable to liquids. Polycarbonate foils have proved to be particularly bonded.

The two film layers can be made from coating compounds containing the same polymerizable film former or from coating compounds containing different polymerizable film formers.

The first layer contains a swelling agent and optionally a light scattering filler, while the second layer requires a swelling agent and at least one pigment that strongly scatters light in any case. In addition, the second layer may contain a non-porous filler as well as a porous filler such as diatomaceous earth in a small amount without red blood cells being permeable. The weight ratio of pigment to diatomaceous earth should be at least 2: 1.

By adding a well-swelling swelling agent (i.e., a substance whose volume increases upon absorption of water), it is possible not only to obtain a layer that can be relatively quickly permeated by the sample liquid, but also to provide good red blood cells and also additional Despite the opening effect, it has a blood pigment separation characteristic. The swelling properties should be sufficient for tests in which the coloration rate depends largely on the transmission of the sample liquid through the layer, such as, for example, the glucose test reaction, and the optical detectability is detectable after up to 1 minute. Particularly suitable swelling agents have been demonstrated with methyl vinyl ether maleic anhydride copolymer, xanthan gum and methyl vinyl ether maleic acid copolymer.

Diatomaceous earth also refers to diatomaceous earth. It is a laminate formed from a diatom-shaped silicate main chain mined in various places. The diatomaceous earth preferably used has an average particle diameter of 5-15 μl, which is measured by a type 715 laser assembling system sold by Fabish (München, Germany).

The amount of steel light scattering yarn in the second layer is at least 25% by weight relative to the dry, ready-to-use bilayer of the test field. Since the light scattering filler and the strong light scattering pigment are essential for the optical properties of the film layer, the first and second film layers have different fillers and pigments.

The first film layer should contain no fillers or contain fillers whose refractive index is close to the refractive index of water. Silicon dioxide, silicates and aluminum silicates have proven particularly suitable for this. Trade name Sodium aluminum silicate is particularly preferred. It has an average composition of 66 wt% SiO ₂ , 26 wt% Al ₂ O ₃ , 7 wt% Na ₂ O and 1 wt% SO ₃ . Particularly preferred primary particle average particle size is about 0.06 μm.

According to the invention the second layer must scatter light very strongly. Ideally the refractive index of the pigment in the second film layer should be at least 2.5. Therefore, titanium dioxide is preferably used. Particles with an average diameter of about 0.2 to 0.8 μm have proven particularly advantageous. Most particularly preferred is the titanium dioxide type, which is readily processable in anatase modification.

Reagent systems for the detection of certain analytes by color formation are known to those skilled in the art. All components of the reagent system can be located in one film layer. However, it is also possible for the components of the reagent system to be divided between both film layers.

The color field is advantageously located at least partially in the first film layer.

Coloration within the scope of the present invention means any discoloration as well as the transition from white to coloration, and of course, this discoloration associated with the largest possible variation in the maximum absorption wavelength (λ _MAX ) is particularly preferred.

For the optimization of the test field in the diagnostic test carrier according to the invention, it has proved to be particularly advantageous when the two film layers contain a non-blood humectant. Neutral, ie non-charge, wetting agents are particularly preferred for these. Most particularly preferred is N-octanoyl-N-methyl glucamide.

In order to prepare a test field of a diagnostic test carrier according to the invention, each film layer is produced in succession from a homogeneous dispersion of said components, respectively. For this purpose, transparent foil is used as an interposition in order to form the coating compound for 1st film layers. The arc and the layer which apply | coated the coating compound for 1st film layers to a specific layer thickness are dried.

The coating compound for the second layer is also applied to the layer with a thin layer thickness and then dried. After drying, the thickness of the first and second film layers together should be 0.02 mm or less, preferably 0.12 mm or less, particularly preferably 0.08 mm or less. The dried second film layer is preferably about 2 to 5 times thicker than the first film layer.

Test fields made in this way can be placed on a support layer for better operation, and materials conceivable for this layer do not absorb the liquid to be irradiated. This is particularly desirable for so-called non-absorbent materials such as polystyrene, polyvinyl chloride, polyester, polycarbonate or polyamide plastic foil.

However, it is possible to impregnate a water repellent or coat a water-resistant film on an absorbent material such as wood, paper or cardboard, in which case silicone or light fat can be used as a hydrophobing agent, and nitrocellulose or cellulose acetate can be formed into a film. Can be used zero. Metal foil or glass is also suitable as an additional indicating material.

Although in this case a sample derived from blood such as plasma or serum and also other aqueous liquids can also be tested in order to determine the analyte to be detected in the sample liquid, preferably whole blood, according to the invention For test carriers, the detection surface of the test field to observe and measure color formation should be visible through the support layer. This can be achieved through a transparent support layer. However, it is also possible for the support layer to have holes covered with the detection surface of the test field. Thus the detection surface can be seen through the hole. In a preferred embodiment of the diagnostic test carrier according to the invention, there is a hole in the support layer below the detection surface of the test field, from which the detection surface of the test field can be observed. The hole has a somewhat smaller diameter than the smallest line size of the test field so that the test field outside the hole can be placed on and attached to the support layer.

Due to the structure of the test field, especially the two film layers that do not allow red blood cells to pass through the layer and reach the detection plane, only very small amounts are needed for the measurement of the analyte. If the test field has a size of 5 × 6 mm, for example 3 μl of whole blood is sufficient to measure glucose in this liquid. In order for about 15-20 μL to work reliably with larger amounts of sample and to avoid liquid leakage from the test carrier, integrating the test field into the diagnostic test carrier according to the present invention has proved particularly suitable, The test carrier in which the support field comprises a support layer on which the test field is placed, the test field being larger than the test field and covered with a network attached to the support layer outside the test field. Particularly preferred is a diagnostic test carrier according to the invention covered with such reticular tissue. Particularly preferred such reticular tissue of the diagnostic test carrier according to the invention is hydrophilic and lacks capillary activity. Apply an inert cover made of a material impermeable to the sample liquid onto the area of the network that extends beyond the test field, that is, the area of the network that is not placed in the test field, on the site of the network located on the test field. Arrange them in a way that leaves an area for them.

This particularly preferred network of diagnostic test carriers according to the invention should not be capillary activity or absorbent by itself in order to make the sample liquid as fully available as possible in the test field. When the network is immersed in the water perpendicular to the water it was proved that it is suitable to raise the water in the network to less than 2mm. Coarse monofilament that is hydrophilic is preferably used as the reticular tissue. To this end the textile material can be hydrophilic on its own or made hydrophilic, for example by treatment with a swelling agent. Polyester is particularly preferably used as the network material, in which case the network made from this material is used after treatment with a humectant.

The thickness of the network is that the cover over and the layer underneath are absorbed by the residual liquid on the saturation test field and into the mesh of the filled mesh by capillary forces, generally for which the thickness of the network is between 50 and 400 μm. It is advantageous.

The network should have enough netnum to allow the liquid to pass through the network and reach the test field. The nature of the network is that the liquid does not spread horizontally from the network onto the surface of the network, but flows vertically through the network toward the test field.

In a particularly preferred diagnostic test carrier according to the invention described above, the network covering the test field is larger than the underlying test field. Part of the network that extends beyond the test field is anchored to the support layer. Attachment can be accomplished by methods known to those skilled in the art of test carrier art. As an example, it may be attached with a thermoset adhesive or a hard freeze adhesive. Double sided adhesive strips have also proven advantageous. In all cases, however, attaching the reticular tissue to the support layer is important to the extent that the bonded tubular active liquid transfer is possible from the test field to the portion of the reticular tissue attached to the support layer. This capillary blood liquid transfer should be especially possible when the test field is saturated with liquid. Adhesive tapes made of natural or synthetic rubber have proven particularly suitable for processing. It is very particularly advantageous for agents which act to adhere the network to the backing layer having a test field of approximately the same thickness. This acts somewhat as a spacer, keeping the network in front of the continuous plate outside the area of the test field.

An inert cover of sample impermeable, usually water impermeable and non-absorbent material is placed on the network of the diagnostic test carrier of the present invention, which is particularly preferred in such a way that it covers the area of the network outside the test field. Ideally the cover also comes slightly out of the area of the test field. However, in any case, a significant portion of the network covering the test field remains empty. This blank portion of the network represents the sample application area.

Plastic foil has proved to be particularly advantageous as a cover. If it has a different color than the cover and the network, such as white and yellow or white and red, it is possible in this way to very well mark the area to which the sample liquid to be irradiated is to be applied.

One or more printed arrows on the cover, for example, can also clarify the direction, ie the direction in which the end of the diagnostic test carrier according to the invention should be placed or inserted into the measuring instrument.

The sample application area can be achieved particularly simply with a cover using two tape-shaped plastic foils that leave the tape-shaped area of the network covering the test field empty. The cover foil adheres to the network and optionally the support layer. If the foil itself is not an adhesive, a hot melt adhesive or adhesive tape is suitable for this attachment. In any case, however, care should be taken to ensure that the capillary gap created by the reticular tissue remains under the cover so that excess sample liquid can be absorbed from the test field saturated with liquid. The sample application site is preferably located on a hole in the support layer where signal formation can be observed in the test field.

In order to carry out the method for measuring the analyte from whole blood with the diagnostic test carrier according to the invention, blood is applied to the sample application side of the test field and color formation is observed on the detection side. A frequent cause for false readings in diabetes testing, ie periodic testing of blood for glucose content in diabetics, has been so little sample volume. In the case of the diagnostic test carrier according to the invention having a test field of about 5x6 mm size, 3 μl whole blood is already sufficient to visually evaluate the irradiation results. Since the second film layer of the test field is high light scattering and, conversely, the first layer is light scattering, the formed color is observed with relatively high brightness and chromaticity from the detection surface. This allows accurate measurements despite the small amount of analyte due to the small sample volume.

It is of course also possible to measure the analyte from whole blood with the instrument using a diagnostic test carrier. In order to achieve the quantitative result as accurate as possible, this method is also preferred. For this purpose, the reflectance of the detection site is preferably observed continuously or intermittently for discoloration. The reflectance measurement of the detection surface of the test field is carried out in the form of a measurement series. If the difference between successive measurements is one or more times below the specified value, the measurement is terminated arbitrarily after a further predetermined time. The final reflectance value of the series of measurements is then used to mathematically assess the concentration of the analyte.

Since the method uses accurate criteria to terminate a series of measurements and does not require the point of application of the sample, the sample can also be applied outside of the measuring instrument. In this case, it is sufficient to insert the strip into the instrument at any desired point after application of the sample within the maximum allowable period.

In this case, the method of measurement is not affected within the range of hematocrit values of 20 to 60%, which may indicate that the measurement is irrelevant to the methotcrete when the measurement is performed using the instrument according to the procedure described above. You must wait 2-3 minutes for visual measurements before you can read the hematocrit-independent values.

[Brief Description of Drawings]

The invention diagram is shown schematically in FIGS. 1-9.

1 shows a cross-sectional view of a test field of a diagnostic test carrier according to the invention.

2 shows a perspective view of a particularly preferred diagnostic test carrier according to the invention.

3 shows a top view of the underside of the diagnostic test carrier according to the invention of FIG.

4 is a cross-sectional view of the A-A axis of the diagnostic test carrier of the present invention of FIG.

FIG. 5 shows a partially enlarged view of the cross-sectional view of FIG. 4.

6-9 show calibration lines 1-4, prepared as further described in Example 2. FIG.

Reference numerals used in the drawings have the following meanings.

* Explanation of symbols for the main parts of the drawings

1: test field 2: transparent foil

3: first layer 4: second layer

5: sample application surface 6: detection surface

7: Diagnostic test carrier 8: Support layer

9: reticular structure 10: cover

11: Area of network expanded beyond the test field 12: Sample application area

13: hole 14: adhesive tape for the test field

15 spacer 16 capillary active gap

17: sample liquid 18: positioning hole

The cross-sectional view of the test field 1 shown in FIG. 1 of the diagnostic test carrier according to the present invention shows the transparent foil 2 to which the first film layer 3 is applied. The first film layer 3 is covered with the second film layer 4. Preparation of the test field 1 of the test carrier according to the invention, that is, covering the transparent foil 2 with the wet coating compound for the first film layer 3, and then drying the dried first film layer 3 with the second It coat | covers with the wet coating compound for films (4), and the 1st film layer 3 fully adheres between layers between layers and the transparent foil (2). The blood to be investigated for its contents is applied to the sample application surface 5 of the test field 1 of the test carrier according to the invention. If the analyte is present in the sample, it is possible to observe color formation from the detection face 6 of the test field 1 of the test carrier according to the invention, the intensity of which depends on the amount of the analyte in the sample. .

A particularly preferred diagnostic test carrier 7 according to the invention, shown in perspective view in FIG. 2 and in cross-sectional view in FIG. 4, is in the form of a test strip. On the support layer 8 is placed a test field 1 covered with a larger network 9. The network 9 is attached to the support layer 8 adjacent to the test field 1 by spacers 15. This spacer 15 may be a hot melt adhesive region or a double sided adhesive tape for fixing the network 9 on the support layer 8. Ideally the spacer 15 has a thickness approximately equal to the test field 1. The layer acting as the cover 10 is attached to the support layer 8 and the network 9. It is arranged to cover the area of the network 9 which extends beyond the test field 1. The cover 10 also extends slightly beyond the test field 1. However, this leaves most of the portion of the network 9 covering the test field 1 empty. This area represents the sample application site 12. The sample liquid 17 to be irradiated is applied thereto. The positioning hole 18 allows the test strip to be held in the correct predetermined position of the instrument when measuring with an instrument such as by a reflectometer. This can be achieved, for example, with a pin which is inserted into the position hole 18 to fix the test carrier 7 at a predetermined position. The left cover 1 includes a printed arrow that the user must place or insert the end of the test carrier 7 into the measuring instrument.

FIG. 5 shows an enlarged cross section of a particularly preferred diagnostic test carrier according to the invention as shown in FIGS. 2 and 4. This figure is for explaining how to measure the analyte in the sample liquid, such as glucose in whole blood. For this measurement, blood is applied to the sample application site 12 of the network 9. The liquid penetrates the network 9 vertically and reaches the test field 1. In the case of blood as the sample liquid, red blood cells are retained while plasma and serum reach the layers 3 and 4 of the test field 1. If sufficient sample solution is applied in the form of whole blood, the spot or serum is spread in the test fields in the first and second film layers 3, 4 on the entire area of the test field 1. If the volume of liquid is very small, the test field 1 can absorb all of the overlying network 9. This is because the network (9) itself has no capillary activity. In the case of heavy to bulk liquids, the empty space of the network 9 on the test field 1 is filled first, followed by the capillary space under the cover 10. In order for this capillary space to function properly, it is necessary for the cover 10 to at least slightly overlap the area of the test field 1 under the network 9. The detection surface of the test field 1 can be observed through the hole 13. In contrast, a plan view of the lower part of the diagnostic test carrier according to FIGS. 2, 4 and 5 is shown in FIG. 3. If the analyte is present in the applied sample liquid, the color of the detection face 6 of the test field 1 will change. Color forms chromaticity, which is the magnitude of the analyte in the sample liquid.

The invention is further elucidated in the following examples.

Example 1

Preparation of a Diagnostic Test Carrier According to the Invention

The test carrier according to FIG. 2 is prepared in the following working steps: A 5 mm wide double-sided adhesive tape (polyester support and synthetic rubber adhesive) is placed on a polyester support layer containing titanium dioxide. The composite is co-drilled with holes 6 mm apart to make a measuring hole. The double sided adhesive then removes the protective paper.

A test field consisting of two film layers is prepared as follows: A. The following components are added with a beaker as a pure substance or in the form of a stock solution with the following composition and mixed by stirring:

Water: 820.0g

Citric Acid Monohydrate: .5g

Calcium Chloride Dihydrate: 0.5g

Sodium Hydroxide: 1.4g

Xanthan Rubber: 3.4g

Tetraethylammonium Chloride: 2.0g

N-octanoyl-N-methyl-glucamide: 2.1 g

Polyvinylpyrrolidone (MW 5000) 3.5g

(Sodium aluminum silicate): 62.1 g

Polyvinylpropionate dispersion (50 wt% in water): 60.8 g

Bis- (2-hydroxyethyl)-(4-hydroxyiminocyclohexa-2,5-dienyridine) -ammonium chloride: 1.2 g

2,18-phosphomolybdate sodium salt: 16.1 g

Pyrroloquinoline-quinone: 32 mg

Glucose dehydrogenase obtained from Acinetobacter Calcoaceticus, EC 1.1.99.17: 1.7 MU (2.4 g)

1.6 g of 1-hexanol

1-methoxy-2-propanol: 20.4 g

After the whole composition was stored at pH 6 with NaOH, it was applied by drying to an area weight of 89 g / qm on a polycarbonate foil having a thickness of 125 µm.

B. The following ingredients are added together to the beaker as a pure substance or in the form of a stock solution in the following composition and mixed by mixing:

Water: 579.7 g

Sodium Hydroxide: 3.4g

(Methyl vinyl ether maleic acid copolymer): 13.8 g

N-octanoyl-N-methyl-glucamide: 3.6 g

Tetraethylammonium Chloride: 9.7g

Polyvinylpyrrolidone (MW 25000): 20.2 g

Titanium Dioxide: 177.1g

Diatomaceous Earth: 55.3g

Polyvinylpropionate dispersion (50 wt% in water): 70.6 g

2,18-phosphomolybdate hexasodium salt: 44.3 g

Hexacyanoferrite potassium (III): 0.3 g

1-hexanol: 1.6 g

1-methoxy-2-propanol: 20.4 g

After adjusting to pH 6 with the pomace composition NaOH, it is applied to a coated polycarbonate foil as described in A at an area weight of 104 g / qm and dried.

The strip of 5 mm width of the detection layer prepared in this manner is adhered to the support layer precisely on the thin surface of the perforated double-sided adhesive tape.

The double-sided adhesive tape (PVC support and natural rubber adhesive) as a spacer is adhered to both sides of the support foil and directly in contact with the detection layer. In this embodiment, one spacer is 6 mm and the other is 9 mm wide. Then, the protective foil of the double-sided adhesive tape is removed.

A yellow, coarse, single yarn polyester fabric Scrynel PE 280 HC (Zurcher Beuteltuchfabrik, Ruschlikon, Switzerland) impregnated with a humectant is placed on the composite structure and pressed and bonded.

Two single-sided adhesive tapes (PVC support and natural rubber adhesive) are glued onto the yellow network as a cover in such a way that the spacer is completely covered and still at least slightly overlaps with the reaction zone.

The tape material is cut into a 6 mm wide test carrier in such a way that the measuring hole is in the middle of the test carrier.

Example 2

Hematocrit-independent of the test carrier according to the present invention

The test carrier in Example 1 can be measured with a reflectometer. The reflectance value, which is the magnitude of chromaticity, can be converted to glucose concentration when black lines are available. If the term “relative reflectance” is used, it means the reflectance on the dried test carrier.

A. A large number of venous blood samples with different glucose concentrations are measured to create a calibration line. A calibration line can be prepared using the reflectance value and glucose concentration of this venous blood sample measured by the reference method.

For Assay Variant 1, 10 μL intravenous blood is applied onto the test carrier according to Example 1 and the reflectance is measured after 21 seconds. Calibration line 1 (FIG. 6) is made by rare calculation from the median reflectance of 10 test carriers and the reference value of a blood sample.

For Assay Variant 2, 10 μL intravenous blood was also applied onto the test carrier according to Example 1 and the reflectance measured after 30 seconds. Assay line 2 (FIG. 7) is prepared by rare calculation from the median reflectivity of the ten test carriers and the reference value of the blood sample.

For Assay Variant 3, 10 μL intravenous blood is also applied to the test carrier according to Example 1 and the reflectance is measured at 3 second intervals. When the difference in reflectance is 0.3 or less twice in succession, the measurement is terminated and evaluated using the reflectance value. Calibration line 3 (FIG. 8) is prepared by rare calculation from the median reflectance of the ten test carriers and the reference value of the blood sample.

For Assay Variant 4, 10 μL intravenous blood is also applied to the test carrier according to Example 1 and the reflectance is measured at 3 second intervals. When the difference in reflectance becomes 0.9 or less twice in succession, the measurement is terminated and evaluated using the reflectance value. Calibration line 4 (FIG. 9) is prepared by rare calculation from the median reflectance of the ten test carriers and the reference value of the blood sample.

B. Measurement In the case of variant 1, 10 μl vein blood was applied to the test carrier according to example 1 and the reflectance was measured after 21 seconds. Each reflectance is converted to glucose concentration using the corresponding calibration line of FIG. 6. Deviations of accuracy were measured from the median concentration of the ten test carriers and the reference value of the blood sample, which is shown in Table 1.

In the case of measurement variant 2, 10 μL intravenous blood was also applied to the test carrier according to Example 1 and the reflectance was measured after 30 seconds. Each reflectance is converted to glucose concentration using the corresponding calibration line in FIG. Deviations of accuracy were measured from the median concentration of the ten test carriers and the reference value of the blood sample and are shown in Table 2.

In the case of measurement variant 3 according to the invention, 10 μL vein blood is also applied to the test carrier according to example 1 and the reflectance is measured at 3 second intervals. When the difference in reflectance becomes 0.3 or less twice in succession, the measurement is terminated and evaluated using the reflectance value. Each reflectance is converted to glucose concentration using the corresponding calibration line in FIG. 8. Deviations of accuracy were measured from the median concentration of the ten test carriers and the reference value of the blood sample, which is shown in Table 3.

In the case of measurement variant 4 according to the invention, 10 μl intravenous blood is also applied to the test carrier according to example 1 and the reflectance is measured at 3 second intervals. When the difference in reflectance is less than or equal to 0.9 twice in a row, the measurement is terminated and evaluated using the reflectance value. Each reflectance is converted to glucose concentration using the corresponding calibration line in FIG. 9. Deviations in accuracy were measured from the median concentration of the ten test carriers and the reference value of the blood sample, which is shown in Table 4.

In the case of 20% hematocrit, the measurement variants 3 and 4 likewise have little deviation with respect to 30% hemotocrete.

[Effects of the Invention]

The present invention provides a test carrier that can be readily prepared and allows analytes to be measured easily and quickly from whole blood, and the measurements are independent of hematocrit, despite requiring only a very small amount of blood as possible.

Claims (17)

A test field designed in such a way that the sample application surface to which the blood sample is applied and the detection surface where an optically detectable change occurs as a result of the reaction between the analyte and the reagent system and the red blood cells present in the sample do not reach the detection surface A diagnostic test carrier for measuring an analyte from whole blood using a reagent system contained in a carrier comprising a field and a color forming reagent, wherein the test field includes a first parent for consultation with each other. A transparent foil coated with a film layer is included, and the first layer located on the transparent foil scatters light considerably less in the wet state than the covering second layer, and the surface of the foil coated with the first layer opposite to the foil is detected. The surface of the second layer opposite to the surface on which the second layer is placed on the first layer is the sample application surface. The diagnostic test carrier of claim 1, wherein the second layer contains a pigment having a refractive index of at least 2.5 at a concentration of at least 25% by weight relative to the dried double film layer. The film of claim 1, wherein both film layers are formed from a dispersion or emulsion of a polymerizable film former containing a polymerizable film former and a swelling agent in a homogeneous dispersion, and the swelling capacity of the swelling agent is optically determined. A diagnostic test carrier that is high enough to detect a detectable change after detection up to one minute in terms of detection. The diagnostic test carrier according to claim 1 or 2, wherein, as a pigment, the first film layer contains sodium aluminum silicate and the second film layer contains titanium dioxide. The diagnostic test carrier according to claim 1 or 2, wherein both film layers are suitable for red blood cell separation. The diagnostic test carrier according to claim 1 or 2, wherein the dry thickness of the first and second film layers together is at most 0.20 mm. The diagnostic test carrier of claim 6, wherein the second film layer is two to five times thicker than the first film layer. The diagnostic test carrier of claim 1, wherein the coloration reagent is located in the first film layer. The diagnostic test carrier according to claim 1 or 2, wherein the components of the reagent system are distributed between both film layers. The diagnostic test carrier according to claim 1 or 2, wherein the film layer does not contain a hemolytic humectant. The diagnostic test carrier of claim 10, wherein the at least one film layer contains N-octanoyl-N-methyl-glucamide as a wetting agent. Claim 1 to 11 wherein blood is applied to the sample application surface of the test field and the detection surface is observed for color formation, where the color formation intensity is the size of the analyte in the blood. A method of measuring an analyte from whole blood using a diagnostic test carrier as described above. The method of claim 12, wherein the detection surface is observed continuously or intermittently for color formation. The method according to claim 13, wherein the observation is carried out using an instrument in the form of a series of measurements by measuring the color formation, and the continuous measurement of color formation in which the time of evaluation falls once below a predetermined absolute value of the value difference. How to decide. The method according to claim 13, wherein the observation is carried out using an instrument in the form of a series of measurements by measuring color formation, and the time of evaluation is determined by continuous measurement of color formation falling several times below a predetermined absolute value of the value difference. Way. The method of claim 14 or 15, wherein the reaction period is further followed by one or several drops below the absolute value of the value difference. 16. The method of claim 14 or 15, wherein color formation is measured reflectometrically and mathematically assessing the analyte concentration using the last measurement of the measurement series. ※ Note: The disclosure is based on the initial application.